Captain James West (Will Smith) and U. S. Marshall Artemus Gordan (Kevin Kline) must team up to stop crazy inventor Dr. Arliss Loveless (Kenneth Branagh) from carrying out his plans and taking over the United States. These two heros are not similar in style and it causes much friction between the two of them as the brash West constantly bristles the more thoughtful master of disguise Gordan. West and Gordan also find themselves in a battle to woo the beautiful daughter of a scientist that Loveless has kidnapped. Rita Escobar (Salma Hayek) tags along on Gordan's amazing train to help them find her father. Will they be able to stop Loveless from his plans to destroy the almost completed rail line from east to west and take over the country?